The most common and most likely answer to this crossword clue is the 6 plus 4 letter word USE-BY DATE
I've seen this crossword clue in The Guardian
U
S
E
-
B
Y
D
A
T
E
More clues leading to the result USE-BY DATE
- Take advantage of past boyfriend when something goes bad
- Deadline for eating food could perhaps be Tuesday
- Tuesday 7th of September off – 8th of September past it then?
- Could possibly be Tuesday when life ends
- A seedy tub that’s off? It’s no good after this
- See ad and buy product, finally to be cooked now?
Buddy explains!
The straight part
We know that "past it then?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case past it then? = use-by date.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.